In general, in the case that substrates are intended to be connected to each other, two connectors (for example, a plug connector and a receptacle connector) are used. Said two connectors each mainly comprise a plurality of contacts (for example, plug contacts or receptacle contacts), and an insulator made of an electrically insulating material (for example, block or housing) for arranging and holding said contacts. Said two connectors are each connected to a substrate by soldering or the like. The contacts of one of said two connectors are exposed and extended from the insulator and would be deformed depending on some conditions of fitting of the two connectors.
The applicant of the present application has proposed in the past an electrical connector with a structure by which contacts are prevented from being deformed even when two connectors are obliquely fitted, in Japanese Utility Model Application Opened No. H5-69,873 (1993) (Patent literature 1).
According to ABSTRACT of the Japanese Utility Model Application Opened No. H5-69,873 (1993), a rectangular multipolar connector of the prior art is configured that the block of a plug is adapted to be fitted in the enclosure of a socket, so that when the plug is erroneously inserted into the socket in an oblique direction, contacts would be deformed. For the purpose of solving this problem, the block 50 of a socket is formed to be substantially rectangular block-shaped and is provided at its both ends with extensions 52 and 53 whose thicknesses are in a relation of the thickness d of the extensions 53>thickness c of the extensions 52. The enclosure of a plug is formed from two plate-shaped members 20 and 21, whose lengths are determined such that the plate-shaped member 20 is received between the extensions 52 of the block 50, while the plate-shaped member 21 is received between the extensions 53. The distance b between the plate-shaped members 20 and 21 is determined to an extent such that the block 50 except for the extensions 52 and 53 can be snugly fitted between the plate-shaped members 20 and 21. As a result of which, since the width a of the block 50 is larger than the distance b between the plate-shaped members 20 and 21, there cannot be any oblique insertion of the block 50. Moreover, since the lengths of the plate-shaped members 20 and 21 are different from each other, there is no longer any risk of the block and socket being erroneously fitted with each other.
Incidentally, claim of the Japanese Utility Model Application Opened No. H5-69,873 recites a connector comprising a plug connector having a base for holding and fixing a plurality of contacts, said base provided with an enclosure for protecting said contacts, and a socket connector having a base for holding and fixing a plurality of contacts, said base having a block formed with holes for accommodating said contacts, wherein said block of said socket connector is provided at left and right sides of its longitudinal ends with extensions different in thickness between them on both the left and right sides, and said enclosure of said plug connector has lengths adapted to the thicknesses of the extensions provided at the longitudinal ends of the block of said socket connector.
In recent years, on proceeding of miniaturization of electrical connectors, there is an increasing demand for effective reduction in distance between substrates to be connected. In other words, there is the increasing need to reduce the overall height of electrical connectors each comprising a plug connector and a receptacle connector to be fitted with each other. On the other hand, on progressing of the miniaturization of the electrical connectors, it becomes difficult to fit a plug connector into a receptacle connector and consequently plug and receptacle connectors would be frequently obliquely fitted with each other. The oblique fitting of the connectors results in deformation of contacts and hence defective or failed connection. Therefore, the applicant of the present application has proposed the structure as disclosed in the Patent Literature 1.
Moreover, as the result of the miniaturization and reduced overall height of connectors, the contacts are also miniaturized so that the contacts become likely to be deformed even at a touch.
Further, even if the requirement of reduced overall height of both the connectors may be fulfilled, this will be attended by a problem of poor contact pressure which does not comply with a requirement and results in defective or failed connection.